Lapping tool



Oct. 13, 1942 L. F. GLAUDE 2,298,367

LAPPING TOOL Filed June 15, 1942 Patented Oct. 13, 1942 UNITED STATES PATENT OFFICE LAPPING TOOL Leopold F. Glaude, Chicago, 111.

Application June 15, 1942, Serial No. 447,189

4 Claims.

This invention relates to devices for lapping cylinders for finishing their inner surfaces.

The main object of this invention is to provide a device of this kind which may be readily adjusted in accurate approximation to any desired diameter and then slightly expanded as the work progresses without disturbing the original adjustment.

A further object is to provide a device of this kind in which the second adjusting means is of resilient character so that it may be used for modifying the pressure of the tool on the work during the progress of the work.

A further object of this invention is to provide a lapping tool of this kind in which the lapping surface may be readily renewed when worn or replaced with laps of different materials according to the nature of the work and in which the elements which make up the remainder of the assemblage may be used indefinitely throughout the lives of successive laps.

A specific embodiment of this invention is shown in the accompanying drawing, in which:

Figure 1 is a longitudinal section of a lapping tool.

Fig. 2 is a transverse section of the same taken on the line 2-2 of Fig. 1.

Fig. 3 is a transverse section taken on the line 3-3 of Fig. l; and

Fig. 4 is a section taken on the line 4-4 of Fig. 1.

In the form shown, the lapping tool comprises a cylindrical body I split longitudinally by a kerf I I that extends nearly to the opposite side of the body I6 and terminates in a longitudinal bore I2 which permits the two semi-cylindrical parts of the body to be sprung apart within limits, with minimum danger of breaking at the bottom of the kerf.

The outer surface of the body I6 is covered with a wearing shell or lap I3 held in place by countersunk screws I 4 so as to be readily replaceable. It is Well known in the art of lapping that certain materials, such as cast iron, copper, lead and others, are preferred for certain kinds of work and certain kinds of abrasives. The shell I3 may be provided with surface perforations 14.1 within which the powdered abrasives may lodge in addition to embedding themselves in the surface of the lapping shell.

The body It] has an axial bore which extends throughout its length, which is conically tapered at I throughout what might be termed the hub portion I6 of the body, and beyond this hub portion of the body, this bore is abruptly enlarged to provide a shoulder I 1 and a counterbore I8, the purpose of which will hereinafter appear.

The body I0 is mounted upon a stem made up of the main driving part I9 and an extension 26. In the form shown, the extension 26 has a conical mandrel portion 2I, which fits the conical bore I5 of the body I6, and has a threaded stud portion 22 which engages a threaded axial socket 23 in the driving portion of the stem. The outer end of the stem extension is also threaded at 24 and is squared at the end 25 to receive a wrench.

The hub portion I6 of the body I6 is provided with an outwardly conical nave 26 which co-acts with a conical cup washer 2I, adjustably held by lock nuts 28 and 29. The driving stem I9 has a somewhat enlarged head 30 at its end which provides an abutment 3I against which the inner end I! of the hub of the body bears. The periphery of this head 30 is splined at 32 to the body Ill for positive driving connection.

The head 30 has a conical shoulder 33 adjacent the portion 34 of the driving stem. This stem portion 34 is of considerably less diameter than the interior of the counterbore I8 and is surrounded by a resilient collar 35 of rubber or the like which fits within the counterbore I9 between the shoulder 33 and a gland member 36. This collar when appropriately compressed between the gland member 36 and the shoulder 33 expands and causes a slight expansion of the diameter of the adjacent end of the body In as indicated by dotted lines 31 in Figure 1. The gland member 36 has a head 38 provided with flat faces 39 for engagement by a wrench by means of which the position of the gland is adjusted, due to its threaded connection with the threaded portion 40 of the stem.

In operation the body I0 is adjusted to the approximate diameter of the cylindrical wall that is to be lapped by first backing ofi the nuts 28 and 29 and the washer 21 and also backing off the gland 36 and then rotating the stem extension 20 with respect to the driving stem I9, so as to shift the mandrel 2I in the proper direction for expanding or contracting the body I0 as may be desired. This adjustment of the body is then fixed by means of the abutment 3| and the cup washer 2! and the nuts 28 and 29.

As the lapping. operation proceeds and it is desired to increase the pressure of the lap upon the surface worked upon, this is accomplished by merely rotating the gland 36 and causing the resilient collar 35 to slightly expand that end of the body I6.

Usually this adjustmentcan be made by turn.

ing the head 38 of the gland by the operator's fingers without disconnecting the tool from power source and without disturbing the initial adjustment of the mandrel 2|. The pressure of the resilient packing element 35 is of cours equal in all directions and the resilient walls of the body I!) yield to this pressure and cause the lap to conform to the surface worked upon.

Although but one specific embodiment of this invention is herein shown and described, it is to be understood that numerous details of the structure shown may be altered or omitted without departing from the spirit of the invention as defined by the following claims.

I claim:

1. A lapping tool, comprising a cylindrical body split longitudinally for lateral expansion and contraction and having an axial bore, a stem concentrically mounted in said body, a collar of resilient compressible material interposed in said borebetween said body and stem, and means on said stem for axially compressing said collar for exerting yielding expanding pressure on said body.

2. A lapping tool, comprising a cylindrical body split longitudinally for lateral expansion and contraction and having an axial bore, said bore being tapered at one part, a stem having a tapered portion fitting said tapered part of said bore, means on said stem to shift said body along said tapered portion for expanding said body, a collar of resilient compressible material interposed in said bore between said body and stem,

and means on said stem for axially compressing said collar for exerting yielding expanding pressure on said body.

3. A lapping tool, comprising a cylindrical body split longitudinally for lateral expansion and contraction and having an axial bore, said bore being tapered at one part, a stem having a tapered portion fitting said tapered part of said bore, means on said stem to shift said body along said tapered portion for expanding said body, means for locking said body to said stem, a collar of resilient compressible material interposed in said bore between said body and stem, and means on said stem for axially compressing said collar for exerting yielding expanding pressure on said body.

4. A lapping tool, comprising a body having an axial bore extending through it and comprising a tapered part at one end and an enlarged counter-bore at the other end, a stem comprising mutuallythreaded telescoping parts, one tapered to fit said tapered bore and the other shouldered to abut said body to shift same along said tapered part, said body being split lengthwise for expansion by said tapered part, a resilient compressible collar bearing concentrically between said body and said second stem part, and a gland member on said second stern part to compress said packing ring for yieldingly xpanding the adjacent part of said body.

LEOPOLD F. GLAUDE. 

